Lipoprotein metabolism in normolipidemic obese women during very low calorie diet: changes in high density lipoprotein.

We examined changes in high density lipoprotein (HDL) metabolism during a very low calorie diet weight reduction program in 6 massively obese normolipidemic women. The diet protocol consisted of a 1st low calorie diet (LCD; 1440, 1280, and 880 kcal daily for 1 week, each, in succession), a 1st very low calorie diet (VLCD; 420 kcal daily for 4 weeks, using Optifast 70), intermission (880 kcal daily for 1 week), the 2nd VLCD (4 weeks) and the 2nd LCD (880 and 1280-1440 kcal daily for 1 week, each). Mean body weight reduction was 18.9 kg. HDL-cholesterol, more specifically HDL2-cholesterol, reduced transiently during the 1st VLCD, intermission, and 2nd VLCD periods, and tended to increase in the 2nd LCD. Apolipoprotein (apo) A-I showed a similar change to HDL-cholesterol. However, apo A-II decreased persistently throughout the weight reduction program, and the apo A-I/apo A-II ratio increased significantly in the later part of the program. Serum triglyceride, apo B, and lipoprotein lipase (LPL) activity in post-heparin plasma did not change. These data suggest that the observed decrease in HDL-cholesterol was not due to a reduction in very low density lipoprotein-derived HDL production or to an LPL deficiency, but was consistent with reduction in chylomicron-derived HDL formation following dietary fat restriction.